The production of hydrogen which is predicted to be the fuel of the future has a number
hurdles to overcome. One of the constraints is cost of production. However, cost of production can be
significantly reduced considering biowastes as a potential and cheap renewable substrate for hydrogen
production. The wastes are a result of the many activities of humans leading to wastes generation and
includes household, municipal, agricultural and industrial wastes. Further, the microbial diversity
available enables us to select the right microorganisms to ferment a particular biowaste in obligate
anaerobic or facultative anaerobic single stage or hybrid system to covert the carbonaceous components
to biohydrogen. The systems can be operated with an axenic culture or a consortia of microbial cultures.
Factors that affect microbial growth need to be optimized and the systems can be operated in a
continuous mode. Further, this approach leads to dual benefits, that is, a simultaneous biohydrogen – a
green fuel production and pollution load reduction for the industry. Cost saving technologies are always
attractive to industry where cost of waste management is high. The aim of this review is to summarise
the possible technologies that combine utilisation of biowastes with production of biohydrogen. This
will be attractive to industry as the cost of management of the biowastes can be off set by the alternative
green fuel produced during the process. When biowastes are utilised as energy substrates for
biohydrogen producing microbes.
Keywords: Biohydrogen, photofermentation, heterotrophic bacteria, biowastes, hybrid systems,
phototrophic bacteria, biomass, agroindustrial residues, Rhodopseudomonas palustris, palm oil mill
effluent, biofuel.
